Experimental Demonstration of an Optic-DAC Based Transmitter Structure

In this paper, an optical-DAC (ODAC) based transmitter design is proposed for indoor visible light communication (VLC) applications. The proposed design is practically realized and the communication performance of the experimental VLC system is investigated. In the ODAC transmitter, multilevel communication signal can be generated optically by independently switching light emitting diode (LED) groups with different powers. In this way, multilevel modulation techniques in VLC systems can be realized through a simple transmitter structure that can be digitally driven. In the proposed transmitter design, unlike the existing ODAC-based VLC transmitters in the literature, metal oxide semiconductor field effect transistors (MOSFET) are used as switching elements in order to drive high-power LED for ambient illumination and communication. In the experimental studies, an offline VLC system using the designed ODAC-based transmitter with a power of approximately 10 W is tested at different switching speeds and distances. The results show that by implementing 8 PAM modulation in the proposed transmitter design, a data transmission rate of 6.264 Mbps is successfully achieved.